This invention relates to sliding electric contacts for high currents and particularly for rf applications.
Sliding contacts are used in applications where easy adjustments are desired such as in resonant cavity tuning. A common application is in coaxial cavities tuned by a sliding short. The short must make electrical contact between the inner and outer conductor of the coaxial line and be easily movable. A suitable arrangement of contact "fingers" is often used successfully at low powers. However, at high powers, much more complicated clamping contacts, which must be released to move, have usually been used. To date, no simple arrangement using fingers is capable of reliably conducting high currents.
One of the difficulties with arrangements using fingers is that it is difficult to provide a sufficiently large number of contact elements per unit length. Also, no known material combines both high conductivity and good spring properties.
Another difficulty is the requirement for the conduction of heat away from the contact point.